The present invention No. I relates to an efficient method for the preparation of a polyester block copolymer which is excellent in heat resistance and hydrolysis resistance, in which lactones are addition-polymerized onto a crystalline aromatic polyester.
The present invention No. II relates to a method for the preparation of a polyester block copolymer which is excellent in heat resistance and hydrolysis resistance, and which has a higher molecular weight, in which the polyester block copolymer obtained in the present invention No. I is further allowed to react in a solid state.
The present invention No. III relates to a polyester block copolymer composition which is excellent in heat resistance and hydrolysis resistance, color hue, and melt viscosity stability, and a method for the preparation thereof.
The present invention No. IV relates to a polyester block copolymer composition which is excellent in heat resistance under a contact with a metal and a polyvinyl chloride (PVC), and relates to a heat-sensitive body for a heater cable in which polyester block copolymer-based resin is employed.
The present invention Nos. V and VI relate to a polyester block copolymer composition which is excellent in a blow-moldability and heat resistance.
The present invention No. VII relates to a polyester block copolymer composition composed of a crystalline aromatic polyester and lactones, and relates to a method for the preparation thereof, and which is excellent in a blow-moldability and heat resistance.